Roll changers are typically employed in connection with web-fed rotary printing, for example, and are used for feeding a web of material, for example a paper web, to a printing press. In web-fed rotary printing, the web of material to be imprinted is unwound from a roll of material. This roll of material is rotatably seated in the roll changer, and it is necessary to maintain a sufficient paper tension in the web when pulling the web of material off the roll of material. When a roll of material becomes almost exhausted, i.e. the web of material wound on the roll of material is substantially unwound, this exhausting or depleted roll of material must be replaced by another fresh roll of material. Therefore, at least two separate holders, for seating two separate rolls of material are provided in roll changers. A roll change from the old or exhausting roll to the new or fresh roll of material can be performed by a manual roll change while the press is stopped. Alternatively, this roll change can be accomplished by a flying roll change, or by a stopped roll change with a web storage device. As soon as the old web of material has been replaced by the fresh web of material, the spent core of the old roll of material is removed from the holder of the roll changer to make room for a fresh roll of material for the next roll change. In other words, following each roll change it is necessary to remove an unwound spent core from the roll changer.
The removal of the spent cores can be performed manually by the operator at the roll changer. If the removal of the used-up cores is intended to be performed automatically, a suitable logistic arrangement for the spent cores in required. It is known in the prior art to transport spent core containers to the roll changer following a roll change. The supply tracks, on which the fresh rolls of material are being transported to the roll changers, are also used for transporting the spent core containers. As a result, it is necessary to provide for the supply of the roll changers with fresh rolls of material and for the removal of wound-off spent cores from the roll changers on a common supply track. This can lead to interferences with the production process, in particular with more complex press lines.
DE 196 11 494 A1 discloses an unwinding system for wound rolls. The spent cores are moved out of the roll changer in their longitudinal direction.
WO 95/20537 A1 shows a roll changer, with an additional lifting arrangement for spent rolls inside the roll changer.
DE 78 17 607 U1 describes an arrangement for suspending and removing bales of material by the use of a carrier driven by a revolving chain.
EP 0 454 634 A2 shows a revolving transport chain for bringing fresh cores to a winding machine.
DE 42 15 739 C2 describes a crane-like arrangement for transporting cores from a storage trough to a container.
A transport cart with a lifting device for a spent roll receiver is known from GB 2 191 967 A.
U.S. Pat. No. 5,934,604 discloses a roll changer with a roll stand, in whose holder at least one roll of material is rotatably seated, and with a first transport device for transporting at least one fresh roll of material. A second transport device is arranged for removing an at least partially unwound spent core. The second transport device is passed through underneath the roll stand transversely with respect to the longitudinal axis of the installed roll of material.
JP 10-120258 A shows a roll changer where the removal of the spent core takes place in approximately the lowest position of the holders of the roll changer.